The effect of acute warming and thermal acclimation on maximum heart rate of the common killifish Fundulus heteroclitus

2019 ◽  
Vol 95 (6) ◽  
pp. 1441-1446 ◽  
Author(s):  
Hamid Safi ◽  
Yangfan Zhang ◽  
Patricia M. Schulte ◽  
Anthony P. Farrell
Keyword(s):  
Heart Rate ◽  
Fundulus Heteroclitus ◽  
Thermal Acclimation ◽  
Maximum Heart Rate ◽  
The Common

Cardiac output in muscular exercise at 5,800 m (19,000 ft)

1964 ◽  
Vol 19 (3) ◽  
pp. 441-447 ◽  
Author(s):  
L. G. C. E. Pugh
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Sea Level ◽  
Indirect Evidence ◽  
Mean Value ◽  
Muscular Exercise ◽  
Maximum Output ◽  
Work Intensity ◽  
Maximum Heart Rate ◽  
Sea Level Pressure

Cardiac output during muscular exercise was estimated by the acetylene technique on four members of the Himalayan Scientific and Mountaineering expedition 1960–1961 at sea level and 5,800 m (19,000 ft). The output for a given work intensity at 5,800 m (19,000 ft) was comparable with the output at the same work intensity at sea level, but the maximum output was reduced, the mean value being 16 liters/min, compared with 23 liters/min at sea level. Heart rates during light and moderate exercise were higher than the rates observed at the same work intensity at sea level. The maximum heart rate during exercise was limited to 130–150 beats/min compared with 180–196 beats/min at sea level. The stroke volume at altitude was lower than at sea level at each work rate. On breathing oxygen at sea-level pressure, heart rate for a given work intensity was reduced; but the maximum heart rate increased. Indirect evidence suggested that maximum cardiac output increased but probably not to the sea-level values because of the increased hemoglobin and lower heart rate. altitude acclimatization; cardiac function, work and altitude; hypoxia and cardiac output Submitted on July 29, 1963

Abiotic versus biotic hierarchies in the assembly of parasite populations

Parasitology ◽  
2009 ◽  
Vol 137 (4) ◽  
pp. 743-754 ◽  
Author(s):  
T. K. ANDERSON ◽  
M. V. K. SUKHDEO
Keyword(s):  
Fundulus Heteroclitus ◽  
Classification Tree ◽  
Benthic Invertebrate ◽  
Life Cycles ◽  
Complex Life Cycles ◽  
Parasite Communities ◽  
Parametric Classification ◽  
The Common ◽  
Correct Category ◽  
Parasite Populations

SUMMARYThe presence or absence of parasites within host populations is the result of a complex of factors, both biotic and abiotic. This study uses a non-parametric classification tree approach to evaluate the relative importance of key abiotic and biotic drivers controlling the presence/absence of parasites with complex life cycles in a sentinel, the common killifish Fundulus heteroclitus. Parasite communities were classified from 480 individuals representing 15 fish from 4 distinct marsh sites in each of 4 consecutive seasons between 2006 and 2007. Abiotic parameters were recorded at continuous water monitoring stations located at each of the 4 sites. Classification trees identified the presence of benthic invertebrate species (Gammarus sp. and Littorina sp.) as the most important variables in determining parasite presence: secondary splitters were dominated by abiotic variables including conductance, pH and temperature. Seventy percent of hosts were successfully classified into the correct category (infected/uninfected) based on only these criteria. The presence of competent definitive hosts was not considered to be an important explanatory variable. These data suggest that the most important determinant of the presence of these parasite populations in the common killifish is the availability of diverse communities of benthic invertebrates.

Abstract 9815: Nadolol Seems to Be Superior to Selective Beta Blockers in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia: Is a Smaller Arrhythmic Window Part of the Explanation?

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Ida Skrinde Leren ◽  
Jørg Saberniak ◽  
Eman Majid ◽  
Trine F Haland ◽  
Thor Edvardsen ◽  
...  
Keyword(s):  
Heart Rate ◽  
Ventricular Tachycardia ◽  
Beta Blockers ◽  
Maximum Tolerated Dose ◽  
Catecholaminergic Polymorphic Ventricular Tachycardia ◽  
Polymorphic Ventricular Tachycardia ◽  
Maximum Heart Rate ◽  
Exercise Tests ◽  
Severe Arrhythmia ◽  
First Choice

Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inheritable arrhythmogenic disease, and typically presents as syncope or sudden cardiac death during exercise. Beta blockers are first choice therapy but little is known about antiarrhythmic effects of different beta blockers in CPVT. Nadolol has shown superior antiarrhythmic effect in other cardiomyopathies. Hypothesis: We hypothesized that nadolol is superior to selective beta blockers in arrhythmia protection in CPVT patients. Methods: We included 34 CPVT patients (age 34±19 yrs, 44% female, 88% RYR2 mutation positive). We serially performed 2 bicycle exercise tests in each patient; 1)>6 weeks on maximum tolerated dose of selective beta blockers. 2)>6 weeks on maximum tolerated dose of nadolol. We recorded resting and maximum heart rate (HR), HR at first arrhythmia and the most severe arrhythmia occurring. Arrhythmic window was defined as the difference between maximum HR and HR at first arrhythmia. Severity of arrhythmias was scored as arrhythmic score: no arrhythmias (0point), single ventricular extra systoles (1point), bigemini (2points), couplets (3points) and nonsustained VT (4points). Results: Resting HR was similar on nadolol and selective beta blockers (54±10bpm vs. 56±14bpm, p=0.50), while maximum heart rate was lower on nadolol (122±21bpm vs. 139±24bpm, p<0.01). First arrhythmias occurred at similar HR at both exercise tests (113±21bpm vs. 113±19bpm, p=1.0). Consequently, arrhythmic window was smaller during nadolol treatment (17±10bpm vs. 32±26bpm, p=0.03) (Figure) and also the arrhythmic score was lower than on selective beta blockers (1.1±1.2 vs. 2.4±0.9, p<0.01). Conclusion: Arrhythmic score was lower on nadolol compared to selective beta blockers. Also, arrhythmic window, representing the span of heart rates where arrhythmias may occur and progress in severity, was smaller. This suggests that nadolol should be the beta blocker of choice in CPVT patients.

Comparative study of equations of estimate of the maximum heart rate

2004 ◽  
Vol 3 (2) ◽  
pp. 108-114
Author(s):  
Fernando Policarpo Barbosa ◽  
Hildeamo Bonifácio Oliveira ◽  
Paula Roquetti Fernandes ◽  
José Fernandes Filho
Keyword(s):  
Heart Rate ◽  
Comparative Study ◽  
Maximum Heart Rate

Heart Rate Response to Exercise

2018 ◽  
pp. 437-445
Author(s):  
Gregory S. Thomas
Keyword(s):  
Heart Rate ◽  
Physical Fitness ◽  
Sample Size ◽  
Older Persons ◽  
Heart Rate Response ◽  
Large Sample Size ◽  
Maximum Heart Rate ◽  
Large Sample ◽  
Response To Exercise

The chapter Heart Rate Response to Exercise reviews the studies performed to estimate a patient’s maximum predicted heart rate. While the commonly used formula (220 – age), developed in 1971, is easy to remember, it underestimates the actual maximum heart rate in older persons. Studies of large sample size have found the maximum heart rate to be relatively independent of sex and physical fitness but to incrementally decline with age. The decrease with age is less than 1 beat per minute per year, however. A more accurate and recommended formula is [(208) – (0.7)(age)] as developed by Tanaka and colleagues.

Gut-brain signaling of water absorption inhibits vasopressin in rats

1995 ◽  
Vol 268 (1) ◽  
pp. R236-R247 ◽  
Author(s):  
A. J. Baertschi ◽  
R. A. Pence
Keyword(s):  
Heart Rate ◽  
Water Absorption ◽  
Hypertonic Saline ◽  
Maximal Inhibition ◽  
Water Infusion ◽  
Vagal Nerves ◽  
Dependent Inhibition ◽  
Cervical Vagotomy ◽  
The Common ◽  
Highly Correlated

The mechanism for inhibition of vasopressin (AVP) by gastric water infusion was examined in 24- or 48-h dehydrated conscious rats (n = 136 rats, 255 experiments; mean AVP baseline = 6.3 pg/ml). Gastric water infusions of 1 (n = 8), 2.5 (n = 19), and 4 ml (n = 10) caused a volume-dependent inhibition of plasma AVP by -0.31, -1.77*, and -3.02* pg/ml, with decreases of systemic osmolality of -1.06, -1.52, and -4.26* mosmol/kgH2O (* = significant vs. isotonic, Duncan's test). Gastric isotonic infusions (1-4 ml) had no effect or slightly increased AVP. Systemic infusions of 1.25 (n = 6), 2.1 (n = 10), and 6.3 ml (n = 8) inhibited AVP by -0.48, -1.07, and -2.51 pg/ml, with decreases in systemic osmolality of -1.61, -2.77*, and -7.21* mosmol/kgH2O. Systemic isotonic infusions (2.1 and 6.3 ml) slightly inhibited AVP by -0.71 and -0.85 pg/ml. Individual changes in AVP by gastric infusion of 2.5 ml of water did not correlate with changes in systemic osmolality, mean arterial pressure, or heart rate but highly correlated with preinfusion AVP (r = 0.74, P < 0.0001, n = 28). Pretreatment with systemic atropine methyl bromate (0.7 mg/rat), which abolishes the AVP secretion to gastric hypertonic saline, did not affect the AVP response to gastric water infusion (n = 9). Combination of 2.5 ml of gastric water and systemic hypertonic saline prevented the decrease in systemic osmolality and still significantly inhibited plasma AVP. Maximal inhibition of AVP by gastric water was reduced by 62.6% after lesion of the common hepatic vagal branch (n = 5) relative to shams with identical abdominal surgery (n = 6) and by 62.7 and 72.5% after right (n = 11) and left (n = 8) cervical vagotomy relative to 12 shams (P < 0.05). The results show that 1) gastric water absorption is signaled mainly by splanchnic osmosensors, 2) water signaling is atropine insensitive, and 3) the major water-signaling pathway projects through the common hepatic vagal branch and cervical vagal nerves.

Children’s Heart Rates during Physical Education Lessons: A Review

1996 ◽  
Vol 8 (3) ◽  
pp. 215-233 ◽  
Author(s):  
Gareth Stratton
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Physical Education ◽  
Vigorous Physical Activity ◽  
Moderate Physical Activity ◽  
Physical Educators ◽  
Vigorous Activity ◽  
Education Curriculum ◽  
Maximum Heart Rate ◽  
Physically Active

Physical educators have purported to teach children to be physically active and to promote their fitness. To achieve these goals, children should regularly experience moderate-to-vigorous physical activity (MVPA) during physical education lessons. For the purposes of this review, moderate physical activity is that which elicits a heart rate of 50% of maximum heart rate reserve (MHRR), moderate-to-vigorous activity elicits 60% of MHRR, and vigorous activity elicits 75% of MHRR. Duration criteria were set at 50% of lesson time or 20 min. The majority of lessons described in previous reports failed to achieve these criteria, although problems were noted in method and analyses of data. Lessons with physical activity as a direct goal have been successful in increasing MVPA. A greater focus on physical activity is required in the planning and delivery of physical education lessons if the physical activity and fitness goals of the physical education curriculum are to be met.

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